1. Field of the Invention
The present invention relates to nicotinanilide compounds useful as pharmaceutical agents, to methods for their production, to pharmaceutical compositions which include these compounds, and to methods for their use in various therapies.
2. Description of the Related Art
Chemotactic cytokines (chemokines) are a class of potent inflammatory mediators that have the potential to attract specific subsets of leukocytes to sites of inflammation. Chemokines are typically low-molecular-mass (7-9 kd) proteins that can be divided into four subfamilies (CCC or xcex2-subfamily, CXC or xcex1-subfamily, CX3C) and are categorized by their primary amino acid structure. The CXC subfamily is characterized by the two conserved Cys residues (C) near the N-terminus and separated by an amino acid (X). Some of the CXC chemokines, of which IL-8 and GRO-xcex1 are representative, belong further to the ELR+ subfamily (Glu-Leu-Arg) and are important in the recruitment and activation of neutrophils via the CXCR1 and CXCR2 receptors.
The interaction of chemokines with specific cell populations is mediated by G-protein-coupled seven-transmembrane receptors (7TMR). Chemokine receptors can be classified into four groups (CR, CCR, CXCR, CX3CR) based upon their primary amino acid sequence. The CXCR1 receptor binds with high affinity to IL-8 and low affinity to NAP-2, ENA-78 (epithelial cell-derived neutrophil-activating factor), GRO-xcex1, -xcex2, and -xcex3, whereas, CXCR2 binds with high affinity to all of the mentioned CXC chemokines. Both CXCR1 and CXCR2 receptors are found primarily on neutrophils and a subset of T-cells. W. Holmes et al., Science 253:1278 (1991); P. Murphy et al., Science 253:1280 (1991); A. Chuntharapai et al., J. Immunol. 153:5682 (1994); L. Xu et al., J. Leukocyte Biol. 57:335 (1995).
CXCR1 and CXCR2 have been shown to mediate the responses to CXC chemokines in neutrophils (polymorphonuclear neutrophils; PMN) and are essential to the acute inflammatory response. P. Grob et al., J. Biol. Chem. 265:8311 (1990); J. Besemer et al., J. Biol. Chem. 264:17, 409 (1989); A. Samanta et al., J. Exp. Med. 169:1185 (1989); W. Holmes et al., Science 253:1280 (1991); P. Murphy et al., Science 253:1280 (1991). Although both receptors are involved in neutrophil chemotaxis, in vitro studies using human neutrophils have inconclusively shown if chemotaxis is mediated by one or both receptors. IL-8 induced chemotaxis studies using anti-receptor monoclonal antibodies in CXCR1 and CXCR2 cell lines have led to conflicting reports. J. Quan et al., Biochem. Biophys. Res. Commun. 219:405 (1996); A. Chuntharapai et al., J. Immunol. 155:2587 (1995); M. Hammond et al., J. Immunol. 155:1428 (1995). There is also evidence to indicate that the transendothelial migration of CLA+ T-cells is a CXCR2 mediated event. L. Santamaria-Babi et al., Eur. J. Immunol. 26:2056 (1996).
The role, in inflammatory disorders, of neutrophil chemotaxis mediated by the CXCR1 and CXCR2 receptors is generally accepted. It has been reported that neutrophils are implicated in the pathogenesis of the acute respiratory distress syndrome (ARDS) in patients with sepsis. J. Repine et al., Am. Rev. Respir. Dis. 144:251 (1991). A causal role of PMNs in the lung injury associated with trauma is also widely accepted. G. Goldman et al., Ann. Surg. 212:513 (1990); S. Linas et al., Am. J. Physiol. 255:F728 (1988); R Simpson et al., Prog. Clin. Biol. Res. 388:265 (1994); S. Donnelly, Arch. Emerg. Med. 10:108 (1993); S. Donnelly, Resuscitation 28:87 (1994). For example, sepsis-related ARDS patients have increased levels of IL-8, ENA-78, ad GRO-xcex1 in their bronchoalveolar lavage fluids. R. Goodman et al., Am. J. Respir. Crit. Care Med. 154:602 (1996); J. Villard, Am. J. Respir. Crt. Care Med. 152:1549 (1995). Additionally, it has been demonstrated that CXCR1 functions as the single dominant CXC chemokine receptor for neutrophil chemotaxis in patients with sepsis. C. Cummings, J. Immunol. 162:2341 (1999).
High levels of IL-8 and tissue neutrophil infiltration have been observed in the synovial tissues of rheumatoid arthritis patients (H. Endo, Lymphokine Cytokine Res. 10:245 (1991)). Evidence has been presented that GRO-xcex1 and IL-8 are important mediators involved in the recruitment of neutrophils in the early and late phases of lipopolysaccharide-induced (LPS) rabbit arthritis. A. Matsukawa et al., Lab. Invest. 79:591 (1999). The murine CXCR2 receptor has also been shown to be necessary for neutrophilic inflammation in a mouse model of gouty synovitis. R. Terkeltaub et al., Arthritis. Rheum. 41:900 (1998).
CXC chemokines have attracted attention as being important in the development of atherosclerosis. R. Terkeltaub et al., Curr. Opin. Lipidol. 9:397 (1998). The role of CXCR1 and CXCR2 ligands on monocyte function in atherosclerosis in rabbits was published by D. Schwartz et al., J. Clin. Invest. 94:1968 (1994). Knockout mice that lacked CXCR2 expression had diminished lesion size. W. Boisvert et al., J. Clin. Invest. 101:353 (1998).
The involvement of the CXCR2 receptor in the pathological inflammatory response elicited by central nervous system (CNS) cells as related to Alzheimer""s disease is also gaining significant attention. M. Xia et al., J. Neurovirol. 5:32 (1999). Reports have focused on the upregulation of CXCR2 expression on dystrophic neurites of senile plaques. M Xia et al., Am. J. Pathol. 150:1267 (1997); R. Horuk et al., J. Immunol. 158:2882 (1997).
High levels of IL-8 and neutrophil infiltration have been observed in the pathogenesis of a number of other disease indications.
This includes ulcerative colitis (Y. Mahida, Clin. Sci. 82:273 (1992); R. Izzo, Am J. Gastroenterol 87:1447 (1992)) and psoriasis (R. Gillitzer et al., J. Invest. Dermatol. 107:778 (1996); T. Kojima, J. Invest. Dermatol. 101:767 (1993)). CXCR1 and CXCR2 chemokines and their roles in tumor growth and metastasis have been reviewed. J. Wang, J. Immunol. Meth. 220:1 (1998).
To date, a limited number of CXCR1 and CXCR2 antagonists have been reported.
It was reported that a bis-aryl urea was able to selectively inhibit CXCR2 and prevent neutrophil migration and chemotaxis in a rabbit model. J. White, J. Biol. Chem. 273:10095 (1998). Other CXCR1 and CXCR2 receptor antagonists have focused on NH2-terminal truncations and modifications of IL-8, GRO-xcex1, and ELR motifs. S. Jones et al., J. Biol. Chem. 272:16166. Murine neutrophil recruitment in vivo could also be inhibited via CXCR2 receptor blocking using a truncated human GRO-xcex1 analog. There are currently no CXCR1 or CXCR2 receptor antagonist based therapies widely available.
There is a continued need for inhibitors of chemokine-mediated cellular events, such as those giving rise to an inflammatory response. Small molecule antagonists of CXC receptors and their ligands such as GRO-xcex1 and IL-8 would be useful in the control of harmful inflammatory processes as well as important tools for the investigation of receptor-ligand interactions.
The present invention relates to novel nicotinamide compounds useful as pharmaceutical agents, to methods for their production, to pharmaceutical compositions that include these compounds and a pharmaceutical carrier, excipient or diluent, and to pharmaceutical methods of treatment. The compounds of the present invention may be administered to a subject in order to inhibit a chemokine-mediated cellular event. For example, the compounds may inhibit either of IL-8 or GRO-xcex1 driven chemotaxis. In particular, the compounds of the invention are useful for the prophylaxis and/or treatment of diseases or conditions involving inflammation due to neutrophil chemotaxis, i.e., the compounds of the invention may be used to inhibit neutrophil chemotaxis. The present invention also relates to intermediates and processes useful in the preparation of the nicotinamide compounds.
The nicotinamide compounds of the invention may achieve this biological efficacy themselves, or metabolites of the nicotinamide compounds may be primarily responsible for the biological effects observed upon administration of a nicotinamide compound of the invention to a patient. Thus, the nicotinamide compounds of the invention may have biological activity, and/or may function as prodrugs so that one or more metabolites of the nicotinamide compounds has the desired biological activity. formula (I) 
and pharmaceutically acceptable salts thereof. In compounds of the invention,
R1 is selected from 
R2 is selected from 
n is 0, 1, 2 or 3;
X is selected from oxygen and sulfur; and
R3, R4, R5 and R6 are each independently selected from hydrogen, alkyl, heteroalkyl, aryl, aryl(akylene), heteroaryl, heteroaryl(alkylene), carbocycle, carbocycle(alkylene), heterocycle, and heterocycle(alkylene).
In another aspect, the present invention provides composition comprising a compound or compounds of the present invention as set forth herein, and a pharmaceutically acceptable carrier, adjuvant or excipient.
In another aspect, the present invention provide a method for treating an inflammatory event. The method includes administering to a subject in need thereof a therapeutically effective amount of a nicotinamide compound of the present invention. In another aspect, the method includes administering to a subject in need thereof an amount of a nicotinamide compound of the invention, where the amount is effective to inhibit neutrophil chemotaxis.
In another aspect, the present invention provides a method for antagonizing a chemokine receptor in a subject. The method includes administering to a subject in need of thereof, an amount of a nicotinamide compound of the invention where the amount is effective to antagonize a chemokine receptor in the subject.
In another aspect, the present invention provides a method for inhibiting a chemokine-mediated cellular event. The method includes administering to a subject in need thereof an amount of a nicotinamide compound of the invention, where the amount is effective to at least partially inhibit a chemokine-mediated cellular event. The effective amount may be sufficient to inhibit a CXCR1 receptor in the subject. The effective amount may be sufficient to inhibit a CXCR2 receptor in the subject. The chemokine-mediate cellular event may be an IL-8 mediated cellular event. The chemokine-mediated cellular event may be a GRO-xcex1 mediated cellular event. The chemokine-mediated cellular event may be a granulocyte chemotactic protein 2 (GCP-2) mediated cellular event. The chemokine-mediated cellular event may be an epithelial cell-derived neutrophil attractant 78 (ENA-78) mediated cellular event. The chemokine-mediated cellular event may be a melanocyte growth stimulatory activity (MGSA) mediated cellular event. The chemokine-mediated cellular event may be a lipopolysacchaaride-induced CXC chemokine (L1X) mediated cellular event. The chemokine-mediated cellular event may be a GRO-xcex2 mediated cellular event. The chemokine-mediated cellular event may be a GRO-xcex3 mediated cellular event. The chemokine-mediated cellular event may be a neutrophil-activating peptide-2 (NAP-2) mediated cellular event. The chemokine-mediate cellular event may be two or more of an IL-8 mediated cellular event, a GRO-xcex1 mediated cellular event, a granulocyte chemotactic protein 2 (GCP-2) mediated cellular event, an epithelial cell-derived neutrophil attractant 78 (ENA-78) mediated cellular event, a melanocyte growth stimulatory activity (MGSA) mediated cellular event, a lipopolysacchaaride-induced CXC chemokine (L1X) mediated cellular event, a GRO-xcex2 mediated cellular event, a GRO-xcex3 mediated cellular event, and/or a neutrophil-activating peptide-2 (NAP-2) mediated cellular event. GRO-xcex1, granulocyte chemotactic protein 2 (GCP-2), epithelial cell-derived neutrophil attractant 78 (ENA-78), melanocyte growth stimulatory activity (MGSA), lipopolysacchaaride-induced CXC chemokine (L1X), GRO-xcex2, GRO-xcex3, and neutrophil-activating peptide-2 (NAP-2) are exemplary mediated cellular events.
In another aspect, the present invention provides a method for treating a disorder selected from psoriasis, atopic dermatitis, arthritis, asthma, chronic obstructive pulmonary disease, adult respiratory distress syndrome, inflammatory bowel disease, Crohn""s disease, ulcerative colitis, stroke, septic shock, endotoxic shock, gram negative sepsis, toxic shock syndrome, cardiac and renal reperfusion injury, glomerulonephritis, thrombosis, graft vs. host reaction, Alzheimer""s disease, allograft rejections, malaria, restinosis, angiogenesis and undesired hematopoietic stem cells release. The method includes administering to a subject in need thereof, an amount of a nicotinamide compound of the present invention, where the amount is sufficient to treat one or more of the disorders.
In another aspect, the present invention provides a method for inhibiting IL-8 or GRO-xcex1 driven chemotaxis in a subject. The method includes administering to a subject in need thereof, through a therapeutically acceptable manner, a therapeutically effective amount of a nicotinamide compound of the invention.
In these methods, the administration may be, for example, transdermal, oral, intravenous, intramuscular, vaginal, rectal, pulmonary, subcutaneous, sublingual and transmucosal administration.
The present invention also provides for identifying a binding partner to a nicotinamide compound of the present invention. In one method, a plurality of proteins known to be involved in the signaling pathway of chemotaxis are immobilized onto a suitable carrier; then a solution of one or more nicotinamide compounds, in isolation or mixture, as contacted with said proteins; then the presence of compound:protein complex formation is analyzed using surface plasmon resonance (SPR). The signaling pathway of chemotaxis may be an IL-8 or GRO-xcex1 driven event. In another method, the present invention provides for identifying a binding partner to a nicotinamide compound of the present invention where the method includes providing said compound(s) bound to a solid support to provide solid phase compounds; contacting a cell or cell components with said solid phase compounds in isolation or mixture; removing uncomplexed cellular material; and recovering said binding partner from the solid phase compounds. Another method for identifying a binding partner to a nicotinamide compound as disclosed herein comprises: contacting a cell or cell components with nicotinamide compounds as described herein in isolation or in mixture, inducing a chemical reaction which will covalently link the compound to its binding partner, and then isolating and identifying the modified binding partner.
These and other related aspects of the present invention are set forth in more detail below.